Self-priming centrifugal pump



May 13, 1947. A. c. DURDIN, JR 2,420,420

SELF PRIMING CENTRIFUGAL PUMP Filed on. 7, 1943 2 Sheets-Sheet 1 & g g

May 13, 1947.

A. c. DURDIN, JR

SELF PRIMING CENTRIFUGAL PUMP Filed 001:. '7, 1945 2 Shuts-Sheet 2 jnz/eniolnfl flag using 6. DurdzmZ". 2 by fia 0.

kzls I Patented May 13, 1947 SELF-PRIMING CENTRIFUGAL PUMP Augustus C. Durdin, Jr., Lincolnwood, I ll.; The Northern Trust Company executor of said Augustus C. Durdin, Jn, deceased Application October 7, 1943, Serial No. 505,329

Claims. 1

This invention relates ugal pumps and one of its objects is to provide a combination and arrangement of liquid chambers, communicating with each other through the channels of the pump impeller, one of the liquid chambers being in communicating with the suction of the pump and one being in communication with the volute of the pump whereby to pro vide for the self priming of the pump.

Another of its objects is to provide a centrifugal pump with a liquid chamber located below the top of the impeller chamber and opening directly thereto through an opening in the volute and having a discharge passageway for liquid and air.

It is well known that after a conventional centrifugal pumpcn a suction lift has been stopped for a while, if there is a leak in the check valve of the suction or in the suction pipe or if, for any reason, air finds its way into the impeller chamber, when the pump is started it will not pump out the air and prime itself. One cause of this failure to prime is due to the forming of a ring of liquid within the impeller at its circumference which is carried around by the impeller, which liquid ring prevents the air from passing out of the impeller. I have discovered that if this ring can be broken or disturbed at the opening of the liquid chamber where it is in communication with the volute, air will be mixed with the liquid at broken or disrupted sections of the ring and with the liquid discharged into the liquid chamber; this continues until the air is exhausted and the pump functions in the usual manner,

Another object of this invention is to provide a, self priming centrifugal pump capable of pumping liquid containing solid or semisolid matter and having means to reduce the solids and semisolids into smaller pieces whereby they may freely pass through the channels of the impeller and be discharged.

With these and other objects and advantages in view this invention consists in the several novel features of construction, arrangement and to self priming centrif 2 Figure 3 is a vertical longitudinal section taken on the line 33 of Figure 2 and looking in the direction of the arrows, and

Figure 4 is a vertical longitudinal section also taken on the line 3-3 by looking in the direction opposite to the arrows.

Figures 3 and 4 are upon a slightly reduced scale.

Referring to said drawings, which are illustrative of one embodiment of the invention, the reference character In designates a chambered casing of generally rectangular form provided with feet II for supporting it. The upper end of the" casing is formed witha bolting flange I 2 to which are bolted the inlet pipe l3 and the discharge pipe l4 which open respectively to the inlet chamber l5, and the discharge passageway II.

A cross wall composed of a vertical part I! which extends from the top wall I8 of the pump 56 together with the side walls 22, 23 provide walls for the discharge conduit or passageway l6.

Extending laterally from the side Wall 23, 23b is the volute wall 24 of the impeller chamber 25 which opens through an opening 26 at its lower end into a liquid chamber 34 therebelow. The volute wall '24 terminates at a cutoff point 21 and a point 28, with the opening 26 therebetween, and from the cutofl point 21 the wall 24 slope downwardly slightly as at 29 and merges into the side wall 30 From the point 28 the inner face of the wall 24 slopes downward at a slightly greater angle than the part 29 as at 3| and merges into an arcuate wall 32, the lower end of which joins the end wall 30 through a bottom wall 33 and defines the liquid chamber 34. The upright side wall 22 extends up from the bottom wall 33 to the top wall I8, and a side wall 23a extends up from the bottom wall 33 and joins the volute wall 24.

The side wall 23a is formed with a circular opening 35 which is closed by a flanged head 36 bolted and otherwise secured to the side wall 23a and said head closes said opening and together with the side wall 23a forms one side of the impeller chamber 25. The opposite side of the impeller chamber is formed by a. side wall 31 which Joins the volute wall 24. The side wall 11 has a lateral oil'set upright part 38 which Joins the horizontal part 20, the arcuate part I! and the upright part I! of the cross wall, and adjacent its upper end the wall 31 is oii'set inwardly as at 23b and joins the top wall it. At the inlet chamber i the side wall 22 is offset outwardly as at 22c and joins the top wall l8 and is provided with a hand hole 39 which is closed by a hand hole plate 40 bolted or otherwise fastened to the side wall He.

The side wall 38 is formed with a circular opening 4| concentric with the arcuate part 09 of the cross wall and said opening ll opens to the eye of the impeller 42. The impeller is of conventional construction formed with backwardlv curved blades or vanes 43 which extend between side walls 44, 45 and provide channels 48 for the passage of liquid through the impeller. The latter is shown as keyed to the reduced part of the impeller shaft 41 and is further secured thereon by the nut 41a threaded upon a reduced threaded end part of the impeller shaft. The head 38 is provided with a bearing 48 for the impeller shaft and supports the latter concentric with the opening I. The shaft may be driven by an electric motor or from any other suitable source of power.

When used for pumping sludge or other liquid containing solid or semisolid matter. a cutter is is provided, which is keyed upon the impeller shaft contiguous with the inlet face of the impeller and is held in place on the shaft by the nut 41a which in this case bears against the side of the cutter and holds it tightly against the impeller. The cutter 49 comprises a hub 50 from which extends a plurality of cutter blades II that preferably extend tangentially with respect of the axis or the impeller shaft and run to a rim I2 whose internal diameter is approximately the same as that of the eye of the impeller. Some of the blades ll join the impeller blades and form continuations thereof. Cooperating with the cutter 49 is a ring-like cutter member 83 which is secured to the casing wall 31, 30, and projecting radially from the internal edge of the rin member I! is a blade or other cutting member 54 which cooperates with the cutter blades ii to shear of! or cut into smaller pieces solids or semisolids as they enter the eye or the impeller. As is well understood centrifugal pump impellers rotote at high speed and as there may be several cutting blades on the cutter the blades follow each other in rapid succession and cut or shear solids or semisolids into small pieces. whereby they will not interfere with the operation of the impeller nor with any subsequent operation to which the pumped liquid is subjected.

In the operation of the pump the casin and liquid chambers are initially filled with priming water and when started the pump operates in the customary manner of a centrifugal pump. When stopped the inlet chamber, volute chamber. li uid chamber and discharge conduit remain filled with water, and when started in this condition water in the inlet chamber is drawn into the channels between the blades of the impeller and is thrown outward by centrifugal force into the volute and is discharged through the opening 28 into the liquid chamber i l and thence up through the discharge pipe II. If air has entered the inlet pipe it will be drawn into the im eller chamber by the partial vacuum created therein by the rapidly revolving impeller, thereby acting on the water standing in the inlet chamber and when this water has been discharged and a ring of 4 water forms in and around the impeller, then as someof the water is discharged by the impeller through the opening 28 a disturbance is set up in the entrance of the liquid chamber which results in the ring of water around the impeller being ruptured at the opening 28 and air in the interior side of the water ring mixes with the disturbed liquid and is discharged with it through said opening 26 into the liquid chamber 34 and out through the discharge passageway.

What I claim as new and desire to secure by Letters Patent is:

1. A self priming-centrifugal pump comprising in combination a casing having an impeller chamber, a rotary impeller therein, said casing having also an inlet chamber opening to the eye of the impeller and a liquid chamber located wholly below the top of said impeller chamber with only one communicating opening disposed between the volute of the impeller chamber and said liquid chamber, and a discharge passageway opening to and extending from said liquid chamber.

2. A self priming centrifugal pump comprising in combination a casing having an impeller chamber, a. rotary impeller therein formed with several impeller blades, said casing having also an inlet chamber opening to the eye of the impeller and a liquid chamber located wholly below the top of said impeller chamber with only one communicating opening disposed between the volute of the impeller chamber and said liquid chamber, the s end of said opening nearest the impeller providing therewith a cutoff for liquid flow in the direction of rotation of the impeller and a discharge passageway opening to and extending from said liquid chamber.

3. A self priming centrifugal pump comprisin in combination a casing having an impeller chamber, a rotary impeller therein formed with several impeller blades, said casing having also an inlet chamber opening to the eye of the impeller and a liquid chamber located wholly below the top of said impeller chamber, the volute wall of the impeller chamber terminating at two spaced places below the impeller to provide only one communicating opening between the volute of the impeller chamber and the liquid chamber,-

and a discharge passageway opening to and extending up from said liquid chamber.

4. A self priming centrifugal pump comprising in combination a casing having an impeller chamber, a rotary impeller therein formed with several impeller blades, said casing having also an inlet chamber opening to the eye of the impeller and a liquid chamber located wholly below the top of said impeller chamber, the volute wall of the impeller chamber terminating at two spaced places below the impeller to provide only one communicating opening between the volute of the impeller chamber and the liquid chamber, the terminus of the volute wall nearest the impeller providing therewith a cutoff for liquid flow in the direction of rotation of the impeller and a dischamber into which the impeller discharges liquid, there being only one communicating opening disposed below the impeller located between s olute of the impeller chamber and said liquid at amber, and a discharge passageway forming a cor lndation of said liquid chamber.

6. A self priming centrifugal pump comprising '3, casing having a. transverse wall therein dividing the same into an upright inlet chamber and an upright discharge passageway, said inlet chamber having a suction inlet at its upper end and said discharge passageway having a. discharge opening at its upper end, an impeller chamber disposed at one side of said inlet chamber and discharge passageway, a rotary impeller in said impeller chaz'nber having an eye opening to said inlet chamber and having a plurality of impeller blades, 9, liquid chamber located wholly below the top of the impeller chamber and having only one communicating opening in the volute wall of the impeller chamber located below the bxis oi the impeller.

7. A self priming centrifugal pump comprising a casing having side walls, end walls and a transverse wall extending between said side walls and including a vertical portion and a horizontal portion joined therewith, said wall dividing the casing into an inlet chamber and a dischargepassageway, a volute wall extending outward from one of said side walls and terminating at two spaced places at its lower end to provide an opening located below the impeller, other walls providing a. side wall for the volute impeller chamber, a rotary impeller in said impeller chamber having an eye opening to said inlet chamber and having also a plurality of impeller blades, said casing being also formed with a liquid chamber located wholly below the top of the impeller communicating with said impeller chamber solely through said opening and opening to the discharge passageway.

8. In a centrifugal pump, an inlet chamber, a discharge passageway and an impeller chamber, a rotary impeller in said impeller chamber having an eye opening to said inlet chamber through an opening in a. wall thereof, a ring-like cutting member having an opening coincident with the opening in said wall of the inlet chamber and formed with a radially extending cutting blade and a cutting member cooperating with said first mentioned cutting member and rigidly connected with the impeller, said last mentioned cutting member having cutting blades some of which coincide with the ends of the impeller blades and impeller.

form extensions thereof at the eye of the impeller and cooperate with the cutting blade of the first mentioned cutting member to reduce solids and semisolids entering the eye of the impeller.

9, In a centrifugal pump, walls providing an inlet chamber and an impeller chamber, a rotary impeller in said impeller chamber having an eye Opening to the inlet chamber and blades forming passageways extending from the eye to the periphery of the impeller, a stationary ring-like cutting member secured to a wall of the inlet chamber and a rotary cutting member rigidly connected with the rotary impeller, said cutting members having cooperating cutting blades for shearing off material entering the eye of the 10. A self priming centrifugal pump comprisin combination a casing having an impeller chamber, a rotary impeller therein formed with several impeller blades, said casing having also an inlet chamber opening to the eye of the impeller and a liquid chamber below the top of said impeller chamber with a communicating opening disposed between the volute of the impeller chamber and said liquid chamber, and a discharge passageway opening to and extending from said liquid chamber, a. stationary cutting member secured to a wall of the inlet chamber at the opening thereof which opens to the eye of the impeller, and a rotary cutting member rigidly connected with the impeller, said cutting members having cooperating cutting blades for shearing of! material entering the eye of the impeller.

AUGUSTUS C. DURDIN, JR.

REFERENCES CITED I The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 998,300 Parsons July 18, 1911 2,265,758 Klosson Dec. 9, 1941 1,981,025 Bird Nov. 20, 1934 2,264,953 Regar Dec. 2, 1941 2,041,586 Barzen May 19, 1936 2,057,634 Saxe Oct. 13, 1936 1,993,268 Ferguson Mar. 5, 1935 1,972,304 LaBour Sept. 4, 193 1,989,061 Longenecker Jan. 22, 1935 2,002,454 Rupp L May 21, 1935 2,265,758

Klosson Dec. 9, 1941 

